This invention relates to a card-type magnetic recording device, which is mounted to a portable computer for input or output of information to or from the computer.
Insertion of a card-type magnetic recording device in the shape of a PC card into a slot of a portable computer for supply of information from the magnetic recording device to the computer or vice versa permits the computer to increase a processing data capacity and also to provide additional functions.
In such a card-type magnetic recording device, a case body is generally composed of a frame, a frame plate formed together with the frame in one united body and upper and lower covers for covering the upside and the underside of the frame plate.
In addition to the frame plate, a circuit substrate mounted with elements on one surface is housed in the case body in the state of overlap with the frame plate. A space for housing a cartridge formed by housing a disk-shaped recording medium (which will be hereinafter referred to as a disk) in a shell is formed in the case body.
Further, various components such as a recording/reproducing head body for reading and writing information from and to the disk, a drive device for swinging a head arm of the recording/reproducing head body, a drive device (a motor) for revolving the disk, a lock means for holding the disk in the case and an ejector mechanism for ejecting the disk toward the outside of the case are mounted on one surface (the surface on the side of the circuit substrate) of the frame plate.
Most card-type recording devices in general use have dimensions based on PCMCIA standard Type II. According to this standard, dimensions of the case body of the card-type recording device are regulated to be 54.0 mm in width, 85.0 mm in length and 5.0 mm in thickness.
Thus, a considerable contrivance is required for housing the frame plate mounted with various components for recording/reproduction and revolution of the disk on one surface, together with the circuit substrate or the like mounted with the elements on one surface, in the case body having such a narrow space (a small thickness in particular), while securing a cartridge housing space in the case body.
Further, when the head is not in a disk access position, in other words, the head is placed in a standby position without reading or writing information from or to the disk, the head (and the head arm which carries the head) is placed distant from the disk in the radial direction of the disk, and moreover, the head is placed in a location further above the upside of the disk than it is placed in a location for readout of information from the upper side of the disk, and/or further below the underside of the disk than it is placed in a location for readout of information from the underside of the disk.
Thus, it is particularly necessary to take measures to prevent the (upper) head and the head arm from interfering with the other member (an upper cover, for instance) located above the upper head and the head arm, and/or preventing the (lower) head and the head arm from interfering with the other member (the frame plate, particularly) located below the lower head and the head arm, when the head and the head arm are in the standby position within the thin case body.
Further, the head for readout and writing of information from and to the disk is housed in a narrow space in the case body in close proximity to other components, and is therefore easily affected by electromagnetic noise originating from the elements mounted on the circuit substrate or a magnetic field generated from a stator coil as one of constituents of a disk drive motor, resulting in head reading/writing malfunctions.
It is an object of the present invention to secure a space, which is sufficient to permit a magnetic recording/reproducing head mounted on a head arm to be moved between a recording/reproducing position to obtain access of the head to a disk-shaped recording medium loaded in the device and a standby position to place the head in a location distant from the disk-shaped recording medium without interference of the head with other members arranged in the device, in a card-type magnetic recording device having dimensions regulated to meet the standard. Another object is to provide a means of preventing the magnetic recording/reproducing head from being affected by electromagnetic noise and a magnetic field originating from other components or elements close to each other in a limited space.
To attain the above objects, a card-type magnetic recording device according to the present invention comprises a disk housing space for housing a disk-shaped recording medium; a head arm carrying a magnetic recording/reproducing head and causing the magnetic recording/reproducing head to move between a recording/reproducing position to obtain access to the disk-shaped recording medium loaded in the disk housing space and a standby position at a distance from the disk-shaped recording medium; a frame plate which mounts the head arm and a disk drive device for driving the disk-shaped recording medium loaded in the disk housing space, on one surface thereof; and a circuit substrate, located on the other surface of the frame plate in overlap arrangement, having a plurality of elements arranged on the surface opposite to the surface facing the frame plate; wherein the frame plate has an opening or a concave part allowing the magnetic recording/reproducing head placed in the standby position and/or a part of the head arm to be housed therein. Thus, the magnetic recording/reproducing head can be moved between the standby position and the recording/reproducing position without interfering with the frame plate.
The opening formed in the frame plate having a thickness of 0.4 mm permits the magnetic recording/reproducing head placed in the standby position to be lowered further by about 0.4 mm. On the other hand, while the concave part may be formed in the frame plate by reducing the thickness of a part of the frame plate, the permissible length to lower the magnetic recording/reproducing head is limited in this case. However, the concave part formed by projecting the frame plate by means of drawing or the like increases the permissible length to lower the magnetic recording/reproducing head more than that in the above case.
According to one mode of the card-type magnetic recording device according to the present invention, the head arm is composed of an upper arm which carries the magnetic recording/ reproducing head to gain access to the upside of a disk-shaped recording medium and a lower arm carrying the recording/reproducing head to gain access to the underside of the disk-shaped recording medium. Then, a part of the lower head arm and/or the head mounted on the arm may be housed in the opening or the concave part formed in the frame plate, and the distance between the magnetic recording/reproducing head mounted on the upper arm and the magnetic recording/reproducing head mounted on the lower arm in this state is made wider than the distance between the above magnetic recording/reproducing heads placed in the recording/reproducing position.
An electromagnetic shield material such as copper foil is adhered to the surface opposite to the circuit substrate in the frame plate using an adhesive so as to cover the opening. In this case, the copper foil has a thickness of about 40 xcexcm, and the adhesive has a thickness of about 30 xcexcm.
Instead of forming the opening, a concave part may be formed by reducing the thickness of a part of the frame plate. The portion having a reduced thickness is also used for the electromagnetic shield material.
Any digital IC is not arranged in a magnetic recording/reproducing head operation area and its neighborhood area on the circuit substrate, but an analog IC can be arranged in the above areas. Thus, noise originating from the digital IC can be prevented from having an effect on the magnetic recording/reproducing head. The magnetic recording/reproducing head is hardly affected by the analog IC.
Further, the disk drive device is a motor, and a stator of the motor is composed of a plurality of winding parts formed by winding a plurality of cores with coils. However, a core placed in a location corresponding to the magnetic recording/reproducing head operation area is exposed to the outside without being wound with a coil. Thus, the magnetic recording/reproducing head can be prevented from being affected by magnetic noise originating from the winding parts.